How to Build a Window Seat Over a Heating Vent

Set two 24-inch 2-by-4 boards parallel to each other with their largest sides on the working surface. Position two more of these boards on top of them and perpendicular so that the four boards make a perfect square frame, 24 inches to a side.

Drill three holes down through each corner of the square frame, through the top board, into the bottom board but stopping before entering the working surface for a total of 12 holes. Position a 2 1/2-inch wood screw in each hole and tighten them to complete the construction of one leg support. Repeat with four additional boards to construct another leg support.

Have an assistant hold the two frames upright, parallel to each other and about 2 feet apart. Set six 36-inch 2-by-4 boards across the two leg supports so that they evenly overhang both leg supports. Adjust the spacing of these longer seat boards so that they are evenly spaced next to each other with their largest surface touching the leg supports.

Drill two holes through each of the seat boards and into each of the leg supports for a total of 24 holes. Set a 2 1/2-inch wood screw in each hole and tighten them completely.

Position a 2-by-24-by-36-inch piece of foam on top of the bench. Stretch a piece of fabric over the foam and pull it underneath the bench. Staple it 4 inches from the edge of the bench, spacing the staples every 4 inches around the underside of the bench. Continue to staple and stretch until the fabric is completely attached. Cut off any extra fabric.